1. Field of the Invention
The present invention relates to methods for producing electro-optic devices such as organic electroluminescence display devices and surface-conduction electron-emitting display devices, illuminants such as fluorescent phosphors, color filters, and thin film transistors, and a patterning method used in these methods.
2. Description of the Related Art
Electro-optic devices include liquid crystal display devices, electroluminescent display devices, and field emission display devices (FEDs). These devices may optionally use color filters or color illuminants to form color images.
An organic electroluminescent display device includes light-emitting elements for producing red (R), green (G), and blue (B) emissions. These light-emitting elements are conventionally prepared by a liquid jet method, such as an on-demand ink jet method. Specifically, an organic material is jetted onto predetermined regions intended for pixels on a substrate to form organic material layers intended for the active layers (luminescent layer, charge injection layer, charge transport layer, etc.) of the light-emitting elements, and the organic material layers are dried.
For a surface-conduction electron-emitting display device (SED), films of surface-conduction electron-emitting elements can be formed by a liquid jet method. For example, Japanese Patent Laid-Open No. 09-106755 discloses a method in which a metal complex solution for the element films is jetted between each pair of electrodes and dried and then a current is passed through each element film to form a gap in the film.
For the organic electroluminescent display device, a liquid organic EL (electroluminescent) material can be jetted onto pixel regions to form films.
For example, Japanese Patent Laid-Open No. 2002-372921 discloses a method in which banks separating pixel regions are formed in a multilayer structure including an inorganic layer and an organic layer. The banks are then continuously subjected to oxygen plasma treatment and fluorine plasma treatment to modify their surface. Thus, the surface of the lower layer of the bank is turned lyophilic, and the surface of the upper layer is turned liquid-repellent. An organic EL material is jetted onto the surface of the surface-modified substrate. The organic EL material that deposits on the liquid-repellent surface of the upper layer of the bank does not wet the adjacent pixels or spread. On the other hand, the organic EL material that has been applied onto the lyophilic surface of the lower layer of the bank is drawn into the pixels and fixed. Thus, the organic material can be precisely fixed in predetermined pixel regions.
Japanese Patent Laid-Open No. 2000-223270 discloses another method in which a photocatalyst layer is formed on an electrode pattern. The photocatalyst layer is exposed to light with a predetermined pattern to increase the wettability of the photocatalyst layer overlying the electrode. A luminescent layer is then selectively formed on the exposed pixel regions by ink jetting.
However, the method disclosed in Japanese Patent Laid-Open No. 2002-372921 may not form a desired lyophilic pattern and lyophobic pattern unless proper conditions are set for generating plasma.
The methods disclosed in Japanese Patent Laid-Open Nos. 2002-372921 and 2000-223270 require forming a multilayer structure including an inorganic layer and an organic layer, or forming a photocatalyst. This reduces the range of choices in designing the manufacturing process.
In order to apply a functional material to desired regions precisely, or in order to form a precise pattern, all techniques require a surface treatment to provide that regions where liquid is applied have different wettability from the other regions. It is desired that any such surface treatment be simple while not reducing the range of choices in designing the manufacturing process.